Thread: Dado width calculator - version 1

Mike, that looks pretty good and very useful.

Question, are these based on theoretical blade/shim thicknesses. or actual test cuts. If as I suspect they are based on theoretical, you can at times find a discrepancy between the theoretical and the actual width of cut achieved. At least I have. So these make a good starting point, but for really precise work, I would suggest you do a test cut.

A suggestion, perhaps add a column for imperial sizes/fractions, would be handy when working off US plans.

Great job, I will be using this for sure.

Thanks Big Shed
The spreadsheet's strictly theoretical so far, and I'm planning to test it out over Easter. I'd like to find the best fit for commonly available thicknesses of MDF and ply using the chart as a starting point and measuring the test cuts using a vernier. I'm sure there's a reasonable amount of tolerance in the dado set, as well as some minor wobble in the arbor of my saw etc.
I'll post pics as soon as possible.

I took an offcut of plywood, about 100mm wide and 500mm long. Every time I use a new combination, I make a cut on the ply and mark the combination.

Gives the exact width of the various setups, and has the advantage of being able to test pieces in various slots prior to setting up the dados.

Tex

Just install the set and measure it with a digital vernier caliper...

I have the same set.

You can download the instructions from the northwoods site. It has a size matrix in there.

I used a combination of the methods listed above....I use the matrix to get a close figure, test cut, then measure with the digital vernier thingy... if I'm happy with that I put a reference cut in my mdf template strip...in the resulting dado on the mdf test strip I record the set up....

This then allows me to test fit prior to set up with the dado's...

this is hand because 16mm mdf is never 16mm and the same goes for melamine etc....sad really for engineered board it can +-1mm....typically my dado are about .5mm wider than the nominal timber measurement.

Another good thing to do is to make a zero clearance insert for the common dado settings....you can right the set up on the back and it also services as good final test to see if the slot in the insert lines up with your dado pencil marks....

Recently I've added a 17mm setup to cater for the new cheap 17mm laminated boards that bunnies are selling....